diff --git a/src/internal_modules/roc_audio/target_libvorbis/roc_audio/vorbis_encoder.cpp b/src/internal_modules/roc_audio/target_libvorbis/roc_audio/vorbis_encoder.cpp
index 5c083df3b..b9eb200ef 100644
--- a/src/internal_modules/roc_audio/target_libvorbis/roc_audio/vorbis_encoder.cpp
+++ b/src/internal_modules/roc_audio/target_libvorbis/roc_audio/vorbis_encoder.cpp
@@ -13,19 +13,18 @@ namespace roc {
 namespace audio {
 
 VorbisEncoder::VorbisEncoder(const SampleSpec& sample_spec)
-    : sample_spec_(sample_spec)
-    , initialized_(false)
+    : initialized_(false)
     , frame_data_(NULL)
     , frame_size_(0) {
     vorbis_info_init(&vorbis_info_);
-    const int num_channels = static_cast<int>(sample_spec_.num_channels());
-    const int sample_rate = static_cast<int>(sample_spec_.sample_rate());
+
+    const int num_channels = static_cast<int>(sample_spec.num_channels());
+    const int sample_rate = static_cast<int>(sample_spec.sample_rate());
     int ret = vorbis_encode_init_vbr(&vorbis_info_, num_channels, sample_rate, 0.0f);
     if (ret != 0) {
         roc_panic("vorbis encoder: failed to initialize vorbis encoder");
     }
     vorbis_comment_init(&vorbis_comment_);
-    vorbis_comment_add_tag(&vorbis_comment_, "ENCODER", "roc_audio VorbisEncoder");
 
     ret = vorbis_analysis_init(&vorbis_dsp_, &vorbis_info_);
     if (ret != 0) {
@@ -52,12 +51,27 @@ VorbisEncoder::~VorbisEncoder() {
 }
 
 status::StatusCode VorbisEncoder::init_status() const {
-    return initialized_ ? status::StatusOK : status::StatusNoMem;
+    return initialized_ ? status::StatusOK : status::StatusAbort;
 }
 
-size_t VorbisEncoder::encoded_byte_count(size_t n_samples) const {
-    roc_panic("TODO");
-    return 0;
+size_t VorbisEncoder::encoded_byte_count(size_t num_samples) const {
+    if (!initialized_) {
+        return 0;
+    }
+
+    if (vorbis_info_.rate <= 0 || vorbis_info_.channels <= 0
+        || vorbis_info_.bitrate_nominal <= 0) {
+        roc_panic("vorbis encoder: vorbis_info structure has invalid values");
+        return 0;
+    }
+
+    // Average number of bits used per sample, per channel.
+    const size_t bit_width = static_cast<size_t>(
+        (vorbis_info_.bitrate_nominal / vorbis_info_.rate) / vorbis_info_.channels);
+
+    const size_t encoded_bytes = (num_samples * bit_width + 7) / 8;
+
+    return encoded_bytes;
 }
 
 void VorbisEncoder::begin_frame(void* frame_data, size_t frame_size) {
diff --git a/src/internal_modules/roc_audio/target_libvorbis/roc_audio/vorbis_encoder.h b/src/internal_modules/roc_audio/target_libvorbis/roc_audio/vorbis_encoder.h
index 921467520..33043d3d8 100644
--- a/src/internal_modules/roc_audio/target_libvorbis/roc_audio/vorbis_encoder.h
+++ b/src/internal_modules/roc_audio/target_libvorbis/roc_audio/vorbis_encoder.h
@@ -44,7 +44,6 @@ class VorbisEncoder : public IFrameEncoder {
     virtual void end_frame();
 
 private:
-    SampleSpec sample_spec_;
     bool initialized_;
     void* frame_data_;
     size_t frame_size_;